Towing and release mechanism



Nov. 2, 1943. M. J. o. LOBELLE 2,333,621

TOWING AND RELEASE MECHANISM Filed March 10, 1942 5 Sheets-Sheet 1 INI/[NTOR 3 W 477'0 was Nov. 2, 1943. 4. o. LOBELLE' 2,333,621

TOWING AND RELEASEMECHANISM Filed March 10, 1942 5 Sheets-Sheet 2 wrz/vrok 8 Wdloazua Nov. 2, 1943. LOBELLE 2,333,621

TOWING AND RELEASE MECHANISM Filed March 10. 1942 s Sheets-Sheet :5

TOWING AND RELEASE MECHANISM Filed March 10, 1942 5 Sheets-Sheet 4 Nov. 2, 1943. M. J. O. L'OBELLE- 2,333,621

TOWING AND RELEASE MECHANISM Filed March 10, 1942 5 Sheets-Sheet 5 78 I24 (3 J l/VVE/WOA 8y {04465445 Patented Nov. 2, 1943 UNITED STATES PATENT OFFICE 'rowmo AND RELEASE MECHANISM Marcel Jules Odilon Lobelle, Slough, England, as

signor to R. Malcolm Limited, Slough, England, a company of Great Britain .01. zen-33.15)

19 Claims.

use in towing and releasing gliders or other planes which have to be towed in flight, but it is also applicable inany case where a load has to be supported and released with-ease and certainty, for example in the carrying of heavy bombson aircraft. It is an essential requirement of such mechanism that it shall be capable of supporting the pull or the load no matter in which direction it may act upon the eye or plug which is held and released by the mechanism. It must also be possible to effect the release with a comparatively small expenditure of force although the eye or plug must be held positively locked until it is intentionally released.

In carrying the invention into effect an attachment plate is provided with a recess into which a plug fits, the plug generally having an eye upon it for connection to the load or towing cable, and also having a hook-shaped head or projection adapted to engage with a pivoted hook mounted in a socket at the back of the attachment plate, the pivoted book being associated with a locking and release mechanism whereby the hook can be held securely locked in one position and turned to release the plug when required.-- When a, single hook member is used the fitting of the plug into the socket, and of the hook-shaped pro-' jection into the recess,is relied upon to maintain this projection in engagement'with the hook until positivley released therefrom. Alternatively a pair of hooks may be used engaging with the pro:

jection on the plug fromopposite sides, the hooks being linked together for simultaneous operation in closing them upon the-headed projection on the plug, locking them in the closed position, and for releasing them from-this projection when required. With the operating mechanism for the hook or hooks there may be associated a spring-presssed plunger serving as an indicator and normally projecting slightly from the attachment plate when the plug is securely held by the hook or hooks, andwhen the operating member is in the locking position. The arrangement is such that when the operating member begins to move with a view to turning the hook or hooks and so releasing the p ug, the indicator is immediately withdrawn, before any actual releasing can occur. The projection of the indicator from the attachment plate can therefore be relied upon to show that the mechanism is in the fully engaged and locked position.

In one of its aspects the towing and release mechanism according to this invention comprises a plug member normally held engaged by a hook or hooks which is or are held locked in the engaging position until positively operated for releasing purposes, the plug member being formed as a disc for fitting into a recess, with a headed projection for engaging with the hook or hooks, and with an eye or the like for supporting the pull or the load, so that whether the pull on the plug is directly outwards, or isin any other direction which tends to cause the disc to pivot about its edge in the recess, the headed projection of the plug member exerts a force in substantially the same direction on the engaging surface of the hook or hooks, whilst the positiveretractionof the hooker hooks is effective to release the plug immediately no matter in which direction it is beingpulled at themoment of release.

In another aspect, the towing and release mechanism according to the invention comprises a fixed member-with a socket and releasable looking mechanism within the said socket, and a removable member in the form of a plugwith a headed projection adapted to be engaged by the said releasable locking mechanism, a disc which fits'in a recess in the fixed member, and an eye or the like for supporting the load, the construction being such that no matter in which direction below the plane of the disc that the pull of the load may be acting on the eye or the like at the, time of release, the removable plug member will either pivot about theedge-of its disc in the recess ,orwillbe drawn directly away from the recess, and in either case the direction in which the forces are applied between the plug and the releasable locking mechanism when the releasing action begins will be substantially the same. The invention is, illustrated in the accompanying drawings which show by way of example three forms of construction. I

Figure 1 is a side view, partly in section, showing a form of the release mechanism with a single hook, in the engaged position;

i Figure 2 is a similar view partly insection on the line Z2 of Figure 3, showing the hook retracted for releasing the plug member;

, Figure 3. is an end View partly in section on the :line 373 of Figure 2, showing the hook in the same position as in Figure 2;

. Figure. 4 is'a side view, partly in section, on the line.4- -4 of Figure 6, showing a form ofthe release mechanism withapair of hooks, in the engaged position;

Figure 5 shows the same mechanism with the hooks in thereleasing position;

Figure 6 is an end view of the same mechanism as in Figure 4;

Figure '7 is a side elevation of the mechanism of Figure 4;

Figure 8 shows the same mechanism as seen from the opposite side:

Figure 9 is a detail view of the cam shown in Figure 4, illustratingsits action;

Figure 10 "is 'a 'side view, partly in section on the line Iii-40 of Figure 12, showing a modified form of construction, also having a pair of hooks;

Figure 11 shows the constructiomiof Fig-line M) with the hooks in the releasing position;

Figure 12 is an end view of tihe'iconstmcfiion of Figure 10;

Figure 13 is a side elevation of the construction of Figure 10; and

Figure 14 is a detail view of the 63111 :of'the Figure 10 construction, illustrating its action.

Referring first to Figures 1 to 3, '20 is the amtacl'nnent plate which may [be fitted ton part Mm xfinselazgepfaniaeroplsne, for-example, and [I :is. a hollow roasting secured to the -plate by butts 22. 'flheinlug-member has i8, :headed projectinn :2! which :nommally 7511B into the reoess in the washing ;2l mind .-ls engaged by the hook 4 which is :piuotally supported on :8, transverse stud 2i. il'wo s'idezplaites i2 5 are secured lby :bolts 50 tn upward'prozieutions of basting lid and mm slmd 55 3339885 ifirrnughfthese upward projections and ithe side plates 2&6. The 19 mg member ha a disc an which maybe of any suitable shape, and wr'richzrests iagairnst the baseio f the casting 24 :in :a :socket stormed why the zapentme :in :the attadhment plate 320 seen in -:1. mine load'iis supplied to iiihe plug member by an eye :28 which reoe'ives the and x11. (the towing {cable (not showrr) oa anyxother attached element, sand the pull on the ptug can be :appliediin anyldirectinn beyond the plane 0f fithe attachment :plate 20. Er e hook fl operaiesdn a slotat -M H ellow ingthe hock tolbe retracted iasishown :in Figure 2.

The tailpiece 330 of the *h'ook 3-24 is ifor'ked :amIl has a transverse -p'in w supporting cne end :of :a link 52, vi-hose other end is pivotally connected at *38 to a rocking member 34. "li he ro'cher 234 tums ona fined stud securediin the side plates 25 "and the upward *p roj ections of the casting 12 I The rocker *3! has three lanked arms, one oonheated to the dink-32 as above stated, a second carrying a'stiud #6 serving as a pivot ior -'a. latch member and a third connected "by a pivot n to a plunger *89. plunger works in :the sook'et 'of *a member -40 'Whidh is pirvotedeit 4"! in lugs on a bracket '42 attached to debt of the casting 24,, "the plhmger having a flange '43 and the member *Wll having a flange fl betwee'n wl'tidhis 'dis posed'a strong spring 45. This spring tends to hold the rocker $4 "-in the position :of I

Figure l, .and so to extend the link U2, which in 't rrnpresses nutwards=the tailpiecebf the hook 24, holding hooked 'end in "the pds'it'ion for engaging the projection 25 :of the plug memher. The latch member 31 l'ias an arm formed with an eye 5.6 forth'e attachment o'f any suitable .operatingelement (not shown) whereby a pull may be applied to the latch member in the direction of the arlrows'fln Figuresil and 2. The nighthand arm of the latch member is hooked ior .overa transverse pin 4.| extending between the .side plates 2.6.. The end of the arm 45 normally bears upon the head of .aplunge'r 48 which iisguidedina bracket 4.9 attached by bolts 52 to the side plates #5 ,pressed up springs 5|. The end of this plunger normally projects through apertures at 53 in the base of the casting 2| and in the attachment plate 20, as seen in Figure 1. When in this position the end of the plunger can be seen or felt by hand, and it only remains in this position so long as it is depressed by the arm 46 of the latch memher J1. "Lo 'lno'lil'the latmh rmemher iln this positron'a plunger 54 is provided engagingin a socket in the rocker 34 and pressed outwards by a oomparatively strong spring 55.

With this-construction, the rocker 34 and the link '32 act as a toggle between the fixed pivot 55 and the 31] .in the tailpiece 30 of the hodk n-rember'-24, :so holding the hook positively in'the engaging'p'osition, under the action of the mowerf'ul spring 45. Further, the latch 3'! is idol-mad over toward the right in Figure 1, by the action of spring 55, so that its hooked end 46 engages over the pin 41, thus providing an additional positive lack .for .the hook member--24. P-he spri-ngsi] Fare lightsprings which are easily compressed as thelatch .is turned by .the .action of sthe .socketed spring 55 hearing on the plunger 54" .Eorreleasing the -hook24 apull is applied to the eye s55 in the direction of the arrows in Figures 1 and 2 afirst causing the ,latch member to turn until the spring 55 is compressed by the plunger 54, :and thenvcausing -th8zl90k6l to turn against the resistance of spring 45 :so as to break the toggle and draw up the :link 32, until the hook 24 releases the :projection :23 of the plug member, rallowing it to draw away as indioatedsforexample in Figures .2 and-3. No matter -.in which direction the pull on the .eye :28 may bee-applied, .the plug (either pulls away direchly or mocks about the edge of the disc 21 at some point while ithe pnojoction -23 moves away irometlm .-hook 24 Ella-is nnoiieotion is normally trapped between the z-socket of the casting -2| and (the :of the hook 24, while the disc 21 is he r n against (its seating, so that (the plug cannot .-move, and (the :pull upon it in any direction causes 'the protection "23 ,to pull upon the hook 24 with :a dome acting outwardly against the dip of the hook substantially normal to the engaging xf'aces'if they are shaped as shown. As the hook is drawn back, rthe headed projection 23 begins *to move outwardly -either directly or byra rocking movement 'for example as in Figures 2 :and '13, and the "increasing slope of the lip of the hook #24 then :results [in a component of the pulling force tending to :press back the hooklstill durther,.- b ut until the hook 24 begins to-turz-n ther-direotionof vthe force acting between the protection 2-3 and .the hook r24 due to any pull on-the gplug member is in :a plane substantially massing through the supporting stud 4.25.

'Thepullfor releasingipurposesmight of course, beapplied directlyltolthe upper-arm of therocker 34, ibntitis preferable to apply it to the latch .31

piyotedon the rocker, partly to provide .for an increased leverage about .the ,pivot 35, and partly to provide uf-or lasimple form of positive look by v the latchrarmllblengaging.thepin 41.1. This lock releasiugpurposes is applied, is that there is a considerable :movement allowed to the threearmedllatch anemher 31 before .it'begins to move theirocls'ing meniber'3'4,.so that any unintentional orsrnallmoyements of control willnot even begin to move the hook 24 which engages with the projection 23 on the plug, ortend to permit this hook to release the plug. Again, the rocking member 34 itself may be arranged as shown to have a considerable movement on its pivot 35,

while the link 32 connecting it to the tailpiece 30 of the hook'24 turns upon'its cross pin 31, before the pull on this link becomes effective to turn the hookfor releasing the plug. This again ensures that no unintentional 'or partial movements will suflice to effect release of the plug;

In the form of construction shown in Figures 4 to 9 two hooks 69 'areprovide'dadapted to engage'from opposite sides with a headed projection 61 -on the plug member. The hook members 60 are mounted to turn on substantials'tuds 62 which pass'through the casting63, and the tailpieces 64 of the hooks extend upwardly at the back of the casting, each tailpiece being fo'rkedat its end and provided with a pivot 65 for a link 66; The links are connected together at the spindle 61 so that they can act as a toggle to spread the tailpiece as shown in Figure 4, and so to holdithe hooks 60 in the engaging position, the spindle 61 being mounted at its ends in slides 98 which work in slots at 69 in side plates 10 secured to the casting 63. The side plates are connected together at the top by riveted bolt H which has spacers 14 on it, spacing apart inner plates 12 secured by distance piece 13. Riveted bolt 15 and spacers 16 support the lower ends of plates 12, which are slotted similarly to the side plates 16 to let the spindle 61 and slides 68 move therein. The side plates 19 carry an operating shaft 11 which in this example has at one end a pulley 18 around which is lapped an operating cable 19 leading to a distant position from which the release device can be operated. 'The shaft 11 carries cams 86 which in this construction work between the pairs of plates 16, 12 and engage with cam followers 8| in the form of rollers mounted on the spindle 61 between the plates 10 and .12. In'the normal position of the parts, with the hooks 60 closed on the headed projectionfil, as shown in-Figure 4, a

part 3F! of each of the cams 89 bears on the followers 8| and so locks the spindle 61 in the position with the links 66 extended. The shaft 11 has a crank arm 86 which is normally pulled downwardly by a spring 85, ina direction such as to hold the cams 89 in the-locking position of Figure 4. When the cam shaft is turned in a counterclockwise direction from the position of Figure 4 to that of Figure against the action of the spring 85, the locking surfaces 82 first move away from the cam followers 8!, after a turning movement of about which is sufficient to ensure that small or unintentional movements of the control do not start the release, and then a toepiece 84 on each cam engages the follower and lifts the spindle 61 positively from the position of Figure 4 to that of Figure 5. This breaks the toggle between the links 66 and draws together the tailpieces of the hooks 69, causing them to release the headed projection 61 of the plug. The cams 89 are cut away in the centre as seen in Figure 9 to allow clearance for the free movements of the cam followers 8| when being raised by the toe-pieces B4 of the cams. The links 66 are provided with tailpieces 86 connected by members 61 to plungers 88 which work in recesses in the tailpieces 64 of the hooks 99, and are pressed upwards by springs 89. These springs are compressed when the cams 89 are operated to lift the cam followers 81, andto break the toggle between the links 66, as shown in Figure 5, and when construction of Figures 4 to 9; Again the pulley the earns 89 are allowed to move back' underthe action of the spring 65, the springs 89 also act to cause the links 66 to straighten out the toggle again asin Figure 4. The earns therefore'do not require to have surfaces for pressingdown the camifollowers 8l,-but the cam surfaces *82 merely come into locking engagement with the cam followers at the end of this return move: ment of the cams.

The springs 89 serve a further purpose, namely to cushion the movements of the hooks 60 in relation to the control mechanism and the cams, and so to minimise shocks transmitted to the control mechanism during releasing of the load by the hooks. The release may be very sudden as the'hooks are separated, if there is a heavy pull on the eye 90' of the plug member. This member has a groove at 91 in itsidisc portion in which is fitted a collar 92 of rubber or the like. This collar bears against theedge of the socket formed at 93 in the base of the casting 63 when the'plug is held in position in the socket, and acts as a gland preventing the passage 0f'3JlI,'Wat81' and soforth. The collar 92 also forms a bufferto minimise damage by the plug member if it hits any part of the towing or-towed member after release. a

In this form of construction also an indicator is provided consisting of a rod 94 whose end is caused to project slightly from the base of the casting 63 whenthe cam 80 is in the locking position. The rod 94 is pressed downwards by a spring 95, andis guided in a bracket 96 on the casting; Its upper end has a pin-and-slot connection at 91 with the arm 98 of a bell-crank lever pivoted on the casting 63 at 99. The arm I99 of this lever engages with an'arc-shaped cam surface I61 on the face of the pulley 18 as best seen in Figure- 8. When the pulley is turned .in the direction of the arrows in Figures 4, 7 and 8' to causethe cams 89 tooperate the hooks60 for releasing purposes, the cam surface JOI actson the arm 90. to turnthe bell-crank lever and to liftthe indicating rod 94so that its end no longer projects. The'rod is held up until the parts are returned'fully' tothe locking position again.

In place of'the' pulley 18'and cable 19 foriop erating the cams any other suitable operating mechanism can be used and this is illustrated;

only by way of example.

'Figures'lflto 1'4 illustrate a. form of'the release mechanism in manyrespects like that of Figures 4 'to 9, but withcams which draw down the cam followers instead of drawing. them away from the hooksp This has the advantage thatthe device takes up less room rearwardly and can be used in places where-there is not room for the 181 and cable 19 are shown-for operating purposes and'the camshaft" is supportedin side plates I05 attached to the casting 196 in which the hooks -Hi1 operate; The shaft 11 has a crank arm I36 at one end, --towhich is pivoted an. eye I31 forming. an attachment for one end of a tension spring 139, whose other-end is connected toan attachment eye I 38 pivoted on the base of the casting 106-. This spring tendsto hold the parts in the locked position of Figure 10. The towing plug has a headed-projection Hi8 engagedby the hooks, an eye H 0 for carrying the load, anda flange or disc I09 which seats in a socket l l I. inv

the casting 1.06. The hooks are supported on.

pins H2 in the casting, and have tailpieces H3 connected at their ends by links H4 which are. pivoted on a sliding spindle H5. Thi spindle i 'zuided hwapliders :Mii Emit-heslots $1M ;in the side cplates M5,, and .;in intermediate :p'lates 111.8 which are. attaohed'tmthe side plaites 1.05 byrivets dibfiamdispacers asiin theliast described :construotron... illhemazms ilZil-nngagewith-the 10am followers tm-l pndzhe spindle I I5, by locking surfaces 422 as seen rinztull illnes :inilfigune,14,-and-by:toe pieces ms :tor :drauting down fthe cam followers and the spindle H5 when requiredzicrmeleasing the :honks toil. Inthis case :flat springs 5124 secured: by screws ilfirondzhe :tailpieces Hi3 engage withcflats onithezends ch26 iofi'the Brinks l M :tohold the :in the iextended rposition .as shown Figure 1.6., and F130 :oppme 3B, resistance to their movement. when the :spindle aids drawn down by'fitheicams d220, the .aspoings IM :are flexed :by the projectin surfaces :on ithe ends lt26 of the Iinks l lni as seen iin *Figure iii. The "backs of the hooks l 1 abut against collars lzlupon transverse :p'ins (I28 in the casting BT when itheihooks med ally opened as inFigurell.

- The iindicatorin this-case is a rod I30 with *a spring "31 which tends to retracttit, the'top of the rod being connected to a lever P31. pivoted at 33 on the-s'ide-plaite. This lcverdias a boss lflwhich camper-s tes with apro'jedtion 135 :on the back of the cam I20 as shown in Figure 14. When the cam is i'n the "locking position, as shown in full lines "in this figure, "the projection I35 acting on the boss {I434 on lever 132 depresses this lever causing 'theend'of theindicaltor rod 130 to project from the casting I 06 as seeniinFigure 10. When the cam turns for releasing purposes the surfaces M! and 195 separate. and the indicator is retiraoteti by its spring W1.

Each form of the device has been described for convenience as if it were in "a vertical position with the plug underneat'h, but of 'course it can-be used many position, and for towing purposes it would enerally project towards the side .or the rear of the fuselage of the towing ,plane or .tug, and .from the front IQI' side .of .the nose .of the towed member ,or glider. when the device 'is used lfior supporting .bombs {it will generally .be in an upright mosition with the .plug underneath it. In-allcasesmodnatter in which direction the pull on thepluglmay-pome-the engagement of the=disc (m "the nilug with the recess ensures that the headed projection can only pull outwardly either in .ari'rrectline mrraronnd one edge ror (the recess acting as re. ifinlcnum, so that :the :foroes [exerted-on the books 18.1 8 always substantiallydn the samedirection, namely normal to the :surfaces (on the underside of the head which engage with the hooks. For the 'purpose of ensuring release :of the-plug in spite of icingconditions or-t-he likethe h'ookszmay -be formedwith knucklesurfaces just a' bove the head of the'pro'jectionon the -p1ug,-as

shown at I29 in 10E and ll. These knuckle surfaces I29 come close together at the itout if it tends'to stick. Normally of ,course the pull on the plug will ensure that it. drop away the-moment it is released *by the hooks.

The invention is not limited to the details of the mechanism abov describ,ed,.and for example many arrangements of springs are possible for ensuring the return .of the parts to the locking position. The-spring may be arranged'to act dirent .on the slidecarrying the follower, tending sarcasm rozpulliitiinra direction toholdathe links extended zerrdxthezhonksmlosed.

:iEae be arranged :to move exactly onto dine with one another, on ithey may -.be:ar- .rangedntopassthe centre line-p sition so as to actiasm'to gle .positivelyrestrioting turning moveamends ofithe :hooks in itherreleasing directiion. .By adjustment :ofithe -,=posi-tion of the when the hooksmne in the closed condition .-it is possible :to Mary :force required for releasing :pnrposes when the plug visunderload. in some .zcasesizit may be desirable to :arrange tmatters so ithatfhe pull conrtheyplugisactually tending :to spread-the hooks and to push the follower upwards, being restricted :by the spring and .linkage 'so that the fiorcemequireii to finitiate'the :releasing actionmy be made comparatively small. .In all 'cases,ihowever, it will be [essential for the operating mechanism' ho moved positivelyunder manual control before any release can itake place, :ami the cam will exercise apos'rtive flock on the follower fCIVGI the first part of thismovement, preventing any risk :of unintentional or premature release.

1. Towing and'release mechain ism consisting-of a fined member and a releasable p'lug member, said *i'ixed nien'iber comprisingatleast one pivoted hook element, means Tor "locking said hook elemcnt in the engaged position and for "withdraw ing it for releasepand a part "formed with a seating, said plug member comprising a headed prosection adapted to be engaged "by said pivoted hook element, a laterally projecting portion adapted to engage the seating aforesaid, and means i or applying the load to said plug, the engaging'surfaces'between said hook element and thei headed projection of said plug member being within saiii fixed'meniber proximity to "the seat- "which receives the laterally projecting portion :of said plug'member whereby, when the load on the-plug tends to cau-se'it to'rock-about the edge (if the laterally projecting portion on the seating, the forces acting between the engaging surfaces of the headed projection and'hodk element aforesaid are approximately normal 'to said surfaces.

2. Towing and release mechanism consisting of a fixed member and a releasable plug member, the plug member comprising a headed projection, *a laterally projecting port'ion in the neighbourhood cfsaid projection and-extending on all sides to form'a-surface about which the plugmembermay fulcrum'when subjected to a 'pullingforce in any direction "below the plane of said laterally "projecting portion, and means .for applying the load tosaid plug member below 'theplane of said laterally projectingportion, said 'fixed member comprising a 'seatingadapted to receive said laterally projecting portion of .theplug member, means .ior engaging withsaid headed projection adapted to hold said plug member positively engaged, and means for efiecting .release of .such engagement while the plug. member .is under load.

:3. Towin and release mechanism, consisting of a fixed member and a, releasable plug member.

element in the engaging position, actuating-means for turning said rocker against the action of said spring means in order to release said hook element, said plug member comprising a headed projection adapted to be engaged by said hook element, a laterally projecting portion adapted to rest upon the seating in said fixed member, and an eye adapted to take the pull of the load.

4. Towing and release mechanism consisting of afixed member and a releasable plug member, said fixed member comprising a part formed with a seating, at least one hook element and a pivot supporting the same, said hook element having a tail piece extending beyond said pivot, a rocker and means pivotally supporting it in said fixed member, a link connecting an arm of said rocker to the tail piece ofsaid hook element, spring means tending to turn said rocker in a direction such as to extend said link and to hold said hook element in the engaging position, an operating member pivotally mounted on said rocker and iormed with a latch adapted to engage with a part of said fixed member when at rest, a spring tending to turn said operating member in the direction to hold said latch in engagement, and an arm on said operating member whereby it may be pulled back against said spring to release said latch and then to turn said rocker against the action of the sprin means aforesaid, whereby said hook element may be turned for releasing purposes, said plug member comprising a headed projection adapted to be engaged by said hook element, a laterally projecting portion adapted to rest upon the seating in said fixed member, and means for applying a load to the plug member.

5. Towing and release mechanism consisting of a fixed member and a releasable plug member, said fixed member comprising a part formed with a seating, at least one hook element and a pivot supporting the same, said hook element having a tail piece extending beyond said pivot,a rocker and means pivotally supporting it in said fixed member, a link connecting an arm of said rocker to the tail piece of said hook element, spring means tending'to turn said rocker in a direction such as to' extend said link and to hold said hook element in the engaging position, actuating means for turning said rocker against the action of said spring meansin order to release said hook element, an indicator and a spring tending to means tending to hold said hook element in the engaged position, operating means for drawing back said hook element against the spring action and for holding said hook element positively looked in the engaging position, said plug mem-- ber comprising an inwardly projecting portion formed with a complementary surface for engaging said hook element, a laterally projecting portion adapted to seat upon said fixed member, and means for applying a load to said plug member.

7. Towing and release mechanism consisting of a .fixedmember and a releasable plug member, said fixed' member comprising at least one hook elementand a pivotal support therefor, spring means tending'to hold said hook element in theengaged position, operating means; for drawing back said hook element against the springactionand for holdingsaidhook element positively locked in the engaging position, an indicator comprising arod, a springtending to withdraw said rod, and a part operated by the operating meansfor the said hook elementior causing said indicator to project when'said operating means is in the positionoi rest and holding said hook element positively' locked, said plug member comprising an inwardly projecting portion formed with a complementary surface for engaging said hook element, a laterally project ing portion adapted to seat upon said fixed member, andmeans for applyinga load to said plug member, l

, 8. Towing and release mechanism consisting of afixed member and a releasable plug member, said plug member comprising a headed projection, .a portion extending outwardly around the base of; said projection, and means for applying a load to said plug member, said fixed member comprising a recessed part adapted to receive the outwardly projecting portion of said plug member, a pair of hook elements adapted to engage with said headed projection, and oper ating mechanism for separating and bringing together said hook elements, and for locking them in the engaging position.

9. Towing and release mechanism consisting of a fixed member and a releasable plug member, said plug member comprising a headed projection, a portion extending outwardly around the base of said projection, and means for applying.

a load to said plug member, said fixed member comprising a recessed part, adapted to receive the outwardly projecting portion of said plug member, a pair of hook elements adapted to engage with said headed projection, pivotal supports for said hook elements, linkage connecting" together said hook elements for simultaneous,

operation, and cam mechanism adapted tooperate upon said linkage for locking the hook elements inthe engaging position and for separat-.

ing said'hookelements for releasing purposes.

10. Towing and release mechanism consisting of a fixed member and a releasable plug member, said plug member comprising a headed projection, a portion extending outwardly around the, base of said projection, and means for applying hook elements, jointed linkage connecting together the tail pieces, of said hook elements, a

cam follower at a joint in said linkage, and a cam adapted-to operate on said cam follower to lock the linkage in one position with the hook elementsin the position for engagement with said headed projection, and when displaced from that position to move said linkage in adirection such as to'cause said hook elements to separate their" engaging faces.

.11. Towing and releasemechanism consisting of a fixed member and a releasable plug member, said plug member comprising a headed p'ro-v J'ectioma portion extending outwardly around the base; of said projection, and means fort-apply-inga load to said pl'ugmember, said fixed member comprising a recessed part adapted to receive the outwardly projecting portion of 'saiii plugmember, a pairof hook elements 'adapted to engage with said headed projection, and oper atingim'echanism for separating and bringing-together said hook elementsand for locking them in the engaging position, an indicator, a springadapted to retract said indicator; and me'ans' ac tuated by said operating mechanism for moving said indicator to the indicating position only when said operating mechanism is in the-1505i tionfor locking said hook elements in the en gaging position.

12. Towing and release mechanism consisting of a fixed member and a releasable plug' mew-' her, said plugmember comprising a headed pro' jection, a portion extending outwardly around the base of said projection, and means for a ply ing': a load to=said plug member, said fixed -member comprising a{ recessed pa'rt adapted to receive the outwardly projecting portion of said plug member, a pai 'r of hook elements adaptedl to'l engage with said headed "projection;- pii'lotail supports for said hookelements, linkage: connesting. together said h'ook elements-for simul taneous operation, springs associated with said linkagetendingto bias it into the ositionin. which said hook elements are held-in the'zeng ag in'g: position; and cam mechanism adaptedto operateupon said linkage for locking-the' hook elements in the engaging position and for sepalratingsaid hook elementsfor releasing purposes.

13. Towing and release: mechanism consisting." of -atflxed member and arel'easable plug member-,- said plug memberco'mp'rising' a headed-pi oiection, a portionextending outwardly around the: base ofsaid projection,- and means for applying a: load-to said plug member; said-fixed member comprising 'arecessed part adapted toreceive: the outwardly projectingportion of saiw pl ug member, a p'airof hook elements adapted to; err-- ga'ge' with said headed projection, each-of said; hook elements having a projecting tail piecei. pivotal supports-for saidhoo-k elements? jdint'ed linkage connectingtogether the tailpieces ot s'aid heokel'ements, springs acting uponsaid linkagein iii-direction tending to holdit in the-position;- in which said tail pieces are held separated with the-hook elements inthe engaging position atca m folldwer -at a joint in said linkage; andv-aa: can adapted tdoperatoon said cam follower-to lock the linkage one: position with the: hookelements in the positionfor engagement with saidhe'aded pr'c xjectior-i, and when displaced from:- thaitflpo'sition to move said linkage ina y direction. such as-to cause .saidhook elements to separate. at their engaging faces.

14'. Towing and. release mechanism consisting oiafixed member and a releasable plu member; said plug. member comprising a headed zproj'em-F. tiong. a portionsextending outwardly aroundnthe: base of saidv projection, and means. for. applying; a; load. .tosaid plug. member, said fixed; member: comprising a recessed-part adaptedto receive. the; outwardly projecting portion orsaid: plug1m'em-- ber, a,pair .ofhook elements adapted, tow, engage:

with said. headed projection, each of. saidhook; elements having a projectingltailpiece; pivotal: supports for said hook elements; jointed'dinkage; connecting together thetail pieces of said. hook elements,- a cam-lfollower at a joint in saidlink'e: age, meansfor guiding said cam follower. in its;

movementstowards and. away from thehplane'of; the connections .betweeni .said-zlinkage and etaen tailpiecesof said hook elements; and at am adapted to operate onsaid cam follower th lock the linkage in one position'with the hook cw ments in the position 'for' engagement with said headed projection, and when displaced tronr that position to move said-linkage ina direction such as tocause said 'h'oci'e elements to separate" at their engaging faces-1 15a Towing and releasemechanism consisting of a-'- fixed member-"and a releasable plug menther; said plug member comprising aliea-ded projecticn a portiom extending outwardlyaround the base of saidprojection; and means. for applying a load to said plug member, said fixed menubercomprising a recessed partadapted to na ceive the: outwardl projecting: pcrtionoi said plug: membert a pain of hook elements adapted to: engage with-- said headed projection; each= of said-hook elem entshaving a)- p'roiecting' t'ai l piece, pivotal supports: forsaid hook: elements, jointed linkage conneetingi together the taiil' pieces on said hook: elements; at cam fo1lowen atajointimsaid linkageg. and; a. cam adapted. to: operate: on said cam follower to lock. thelinkageinione position with the hook elements inz the. position; for en:- gagemendwith' said: headed projection; andi when displaced,- from that, position: to! move said link. age in, a, direction. such' 843110". cause. saidihookz eie+ ments-tte separateatetheinengaging fiaces, amine dice-ton, and; means: operatech by, saidicaznc adaptied to; project. said indicator: into: the: indicating position'i only: when: said? cam is, locking, the? hook elements; inith'e .positior-nfonengagem'entawithsaid headed -.pro.ie.ction s 16.1, Towing; and"; release: mechanism consisting oi ahfixedz member. and: a; releasable: plug: memher; said plug member.comprisingzaiheadediprce jection a. portion, ex ter-n'iing outwardly around the base,- ot said projeetion-,=, andemeansz apiplying ag load ta .said plug, member; said. fixed memben; comprising; a; recessed, part. adapted, to receive the;outwardly projecting.;portion.ofi said plug, member; a pair; of -hook. elements adapted to engage with said;headed projection; pivotal supports: for; said hook. elements,-. link-age. con-.- neeting; together; said hook; elementsnfior simulataneoushoperation, a strong; spring actingupon said ilin kagetin a ,directiorrlsuch .-as" to: causmsaid hoolc elements: to ,move: into. the engagingposition,., and cam mechanismadapted. to operate upon said. linkage. for; locking, the hook elements in the, engaging positionand, for separating said hoo'l'e elements for releasinglpurposes.against the action. of said strong spring,

I7; Tbwin andjrel'ease, mechanism. consisting of 1a. fixed, member: and a releasablepliig memlier, said fi'x'e'd member" comprisin a part formed with a" seating adapted to. receive. an outwardliz extending portion" of said plfig member; a pair of hook-'- elements. andfpivotai"suppnrtmgimeans therefor; each hook element having a; tailtpiece extending beyond-thepivotal" supports; links com meeting the tail pieces'tof "SEld"h0Uk'Te1'mI1tS," a cam follower at the point of connection-between said links; spring means"tendingjtoiliold sardcam followed ap'o'sition-with -the tail pieccS"'Of,tYTe" hook-elements separated and" the-hook portions iri their engagingpositions; a'cam having adock: i-ng surfaceadapted one positionpf said"cam tdhold sai d eam followerin-the' position whereinthe--hoo1s-portionsof the hook elementware inthe-engaging position; said cam also" l ievfngw lifting SHMaZCe-adapted when the cam i'ii t'url'ie'd fromethelockings-positionrteiitt the cam icilcwer, drawl-vbacknthe-linkscand drawwtemrd$ one on other the tail pieces of said hook elements, whereby the hook portions may be separated, and said plug member comprising an inward projection formed with complementary surfaces adapted for engagement with said hook elements, alaterally projectin portion adapted to engage with the seating of said fixed member, and means for applying a load to said plug member.

18. Towing and release mechanism consisting of a fixed member formed with a seating, and a releasable plug member formed with a laterally projecting part adapted to rest on said seat n a pair of hook elements and means pivotally supporting them in said fixed member, operating mechanism for said hook elements adapted to lock them in the engaging position and, when operated, to separate said hook elements at their effective engaging surfaces, strong spring means tending to hold said operating mechanism in its locking position, said plug member also comprising a part adapted to be engaged by said hook elements for securing said plug member on said seating and means for applying a load to the plug member.

19. Towing and release mechanism consisting of a fixed member and a releasable plu member, said fixed member comprising at least one hook element and a pivotal support therefor, spring means tending to hold said hook element in the engaged position, operating means for drawing back said hook element against the spring action and for holding said hook element positively locked in the engaging position, said hook member also having a part thereof so shaped that when the hook member is drawn back against the spring action the said part will bear upon a portion of said plug member for imparting a positive outward thrust to said plug member, and

'- said plug member comprising an inwardly projecting portion formed with a complementary surface for engaging said hook element, a laterally projecting portion adapted to seat upon said fixed member, and means for applying a load to said plug member.

MAR-GEL JULES ODILON LOBEILE. 

